Designed for plasma units that do not have an integrated ARC Volts divider (most units do not), this card mounts inside the plasma unit and is connected to the Electrode leads and the Work clamp leads inside (raw arc volts). It also has screw terminals to use for the TORCH switch and to pick up an ARC OK signal IF YOUR UNIT has one. The card has test buttons to confirm connections. Our manual covers how to find and interface to most plasma cutters. If you have an older Hypertherm (1000, 1250, 1650) or ThermoDynamics with no voltage divider option (but with internal ARC OK and START signals) then you should order this card with your DTHCII. If your plasma is not setup for automation then you need this card and probably the DCP-01 to get an ARC OK. Raw voltage is divided, filtered and is directly connected through a shielded cable (supplied) to our THC Sensor PWM module. 4 wide connector for other signals are also included. The RAV-01 works with both hand torch and machine torch setups.